[SOLVED] HOW TO CHECK A FIREBIRD VARCHAR() FIELD IS EMPTY ?
lazarus / 16-Databases

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finalist · 2016-01-07 14:20

FOR FIREBIRD TRIGGER
IS THIS CORRECT:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i IF
FIELDofVARCHAR = ´´ THENBEGIN/* .......*/ENDOR THIS IS CORRECT:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i IF
FIELDofVARCHAR is NULL THENBEGIN/* .......*/END

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taazz · 2016-01-07 14:48

Quote from: finalist on January 07, 2016, 03:20:53 pmFOR FIREBIRD
TRIGGER
IS THIS CORRECT:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i IF
FIELDofVARCHAR = ´´ THENBEGIN/* .......*/ENSOR THIS IS CORRECT:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i IF
FIELDofVARCHAR is NULL THENBEGIN/* .......*/ENSBoth are correct and
possible. In a new record with the field set to allow nulls and no
value inserted yet the value will always be null. nothing is stopping
you from passing and empty string to the varchar to empty it and not
being null at the same time though. So which trigger are you talking
about and how is this field defined/created?

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Zoran · 2016-01-07 14:48

Depending on what you actually want, they are both correct in PSQL
(when you put the condition in parenthesis and change the last line
from ENS to END).

It is important that in Firebird (and, as far as I know, in all other
RDBMS-s except Oracle), empty string ('') and null value are two
different things.
So... it really depends on what you actually want... To better
understand null, read Firebird Null Guide

If you want to catch both nulls and empty strings, then do this:
Code: SQL  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i IF
(FieldOfVarchar IS NULL OR FieldOfVarchar = '') THEN